Accumulator plant



June 1, 1943. P. GILL! ACCUMULATOE PLANT Original Filed Feb. 24, 1936 2 Sheets-Sheet l 5460mm Gran/'1 41, TERA/Afar? nan/av 6 M4751? 77/6/4115 INVENTOR Paw! ii/Ii BY J KQ xfiiifTORNEY June 1, 1943.

ACCUMULA'I'OR PLANT Original Filed Feb. 24. 1936 2 Sheets-Sheet 2 ATTORN EY Patented June 1, 1943 UNITED STATES PATENT OFFICE ACCUMULATOR PLANT Paul Gilli, Vienna, Austria; vested in the Alien Property Custodian 1 Claim.

This application is a division of my copending application, U. S. Serial No. 65,271, filed Febru ary 24, 1936, now Patent No. 2,089,915, dated August 10, 1937.

This invention relates to steam power plants and more particularly to plants including high pressure steam accumulators.

One of the objects of my invention is to provide an arrangement whereby the accumulator may be charged at a pressure higher than maximum boiler pressure. This is accomplished by utilizing superheated boiler steam to heat water or generate saturated steam for charging the accumulator. In accordance with my invention, the exchange or heat between the superheated steam and the fluid for charging the accumulator takes place outside the accumulator vessel, thereby eliminating the necessity of conduits for the superheated steam passing through the shell of the accumulator vessel.

The high pressure accumulator steam may be used along with boiler steam to supply high pressure steam consumers as long as the accumulator pressure remains greater than or equal to boiler pressure. After the accumulator pressure has dropped to just below boiler pressure, I provide means, whereby the steam supplied from the accumulator may be utilized to operate a low pressure steam consumer.

A further object of my invention is the provision of means for automatically regulating a system of the kind outlined briefly above.

Further objects and advantages will be apparent from the following description considered in connection with the accompanying drawings which form a part of my specification and of which:

Fig. 1 is a more or less diagrammatical View of a steam plant embodying my invention;

Fig. 2 is an enlarged cross-sectional view of a heat exchange arrangement shown diagrammatically in Fig. 1;

Fig. 3 is a view of a modified form of heat exchange device; and

Fig. 4 is a cross-sectional view of a preferred arrangement for the accumulator vessel shown more or less diagrammatically in Fig. 1.

Referring more particularly to Fig. 1, reference character designates a steam generator including a boiler H and a superheater l2. Steam is' supplied from generator l0 through a main steam line l3 to a high pressure consumer, for instance the high pressure section [4 of a multistage turbine. The turbine also includes a low pressure section l5 and is mechanically connected to a load, such as an alternator Hi. Interposed in conduit I3 is a valve ll controlled by a speed governor I8. The discharge of the turbine is connected to a condenser I9, the condensate from which is lead to hot well 20.

Arranged in heat exchange relation with main steam line I3 is a jacket'23. The upper end of jacket 23 is connected by means of a conduit 24 having a valve 24' with a conduit 25 leading to charging nozzles 26 arranged in the lower part of an accumulator vessel 21. Vessel 21 is one of several accumulator vessels designated by refer ence characters 21 through 34. Conduit 25 is also connected to the main steam line l3, a valve 3! being interposed in conduit 25 between steam line 13 and conduit 24.

A pump 38 is arranged to withdraw liquid from hot well 20 through a conduit 39. Pump 38 discharges into a conduit 40 which leads to the intake of a pump 4|. A valve 42 is disposed in conduit 4| and, as shown, may be arranged to be automatically regulated in accordance with the liquid level in accumulator vessel 28. For this purpose a float 43 is disposed in vessel 28 and is arranged so that a decrease in the liquid level causes valve 42 to open. A conduit 44 connects the lower part of vessel 28 with conduit 40 at a point between valve 42 and pump 4|. A oneway valve 45, permitting flow from the vessel 28, is disposed to conduit 44 and a manually operable valve 46 is connected in parallel with valve 45.

Pump 4| discharges into a conduit 50 which leads through a valve 50' to the lower part of jacket 23 and. in which is disposed a valve 5|. Valve 5| is arranged to be automatically operated in response to the temperature of the steam in main steam line I3 after it has passad in heat exchange relationship with jacket 23. For this purpose a thermostatic element 52 is placed in heat exchange relation with thevsteam line I3, the arrangement being such that an increase in temperature of the steam at this point causes valve 5i to open.

Pump 4| is driven by means of an electric motor 53 mechanically connected thereto. The electric circuit 54 of the motor is arranged to be closed whenever valve 5| is open.. To accomplish this there is shown a contact arm 55 carried by the stem of valve 5| andarranged to close the circuit through another contact arm 56 whenever the valve stem moves downwardly to open the valve. Thus the pump is operated only when valve 5| is open. A similar. arrangement may be employed for controlling the operation of pump 38 so that the pump will function only when valve 42 is open.

Accumulator vessels 21 and 28 are connected oy means of conduits 60 and BI in such a manner that a thermo-circulation of liquid may take place between the two vessels. A conduit 62 leads from near the upper part of vessel 28 and communicates with the lower parts of vessels 29 and 36, a valve 58 being interposed in this conduit. Vessels 29, 3|, and 33 constitute one bank of series-connected vessels which are arranged in parallel with another bank comprising vessels 30, 32 and 34. The conduits leading to the lower parts of the respective vessels are provided with one-way valves 63 arranged to prevent backflow of liquid therethrough. The two uppermost vessels 33 and 34 are provided with water gauges 64.

Steam may be withdrawn from the vessels 33 and 34 in parallel through a conduit 65 in which is placed a regulator valve 66. Valve 66 is automatically regulated in accordance with the steam pressure existing in main steam line [3 in such a manner that a decrease in this steam pressure results in opening the valve. As shown, the stem of valve 66 is connected to a piston 66a, reciprocably mounted in a cylinder 66b, which is connected by a conduit 66c with steam line l3. Thus, an increase in pressure in the steam line is transmitted through conduit 65c and acts on piston 66a to close more or less the valve 65 against the pressure of the steam supplied thereto by the accumulators. Conversely, a decrease in the pressure existing in line 13, permits opening of the valve 66. Conduit 65 leads to a superheater coil 61 located in the steam space of vessel 28 above the end of pipe 62. A conduit in leads from superheater 6'! to main steam line l3, a one-way valve H being disposed in this conduit. A conduit 12 leads from conduit ahead of valve H to the low pressure section l5 of the turbine. Interposed'in this conduit is a valve 13 regulated by speed governor l3 and a valve '14. Valve 14 is arranged to open when the pressure in conduit 70 falls to about the value of the pressure in main steam line [3. To accomplish this, the piston 15 for operating the Valve is subjected on one side to the pressure of the steam in conduit 10, while on the other side to the'pressure exerted by a spring 16 and to the pressure of the steam in line [3. Thus, when the two steam pressures are about equal, the. spring 76 is able to open the valve, but when the pressure in conduit 70 is greater than that in main steam line l3, the valve remains closed. The tension of spring 16 may be selected so that the valve will open while there is still a considerable difference in the steam pressures.

A valve 80 is connected in parallel to valve 63 and is controlled by a float 8| located in either vessel 33 or 34. The arrangement is such that an increase in liquid level in these vessels results in float 8| opening valve 88 whereby steam may be discharged from the accumulators even though valve 63 is closed.

The operation of this plant is as follows:

Water may be initially fed into the accumulator vessels by means of pump 38, manually operable valve 46 being open to permit flow through conduit 44 into vessel 28, or valve 51 may be maintained open and water forced by pumps 33 and 4| through conduit 40, jacket 23 and conduits 24 and 25 to the charging nozzles 26. The accumulator vessels are filled until the proper level is reached in vessels 33 and 34, as indicated by the water gauges 64. The upper lator plant is charged up to boiler pressure.

end of conduit 62 in vessel 28 will determine the water level reached in this vessel, inasmuch as after the upper end of the conduit is submerged, air or steam is trapped thereabove and prevents any further substantial increase in water level.

When first charging the apparatus with steam, valve 31 may be open and steam supplied directly from steam generator I0 until the accumu- By way of example, this pressure may be assumed to be in the neighborhood of 530 lbs. per square inch and steam supplied from the superheater may have a temperature of 850 F. When the accumulator plant has been charged to this pressure, valve 31 is closed and the superheated steam passing through steam line l3 in heat exchange relation with the water supplied to jacket 23 causes the generation therein of hot water or saturated steam at a much higher pressure than the pressure of the superheated steam supplied from generator l0. With superheated steam at 530 lbs. per square inch and 850 F. as a heating medium, saturated steam at 1700 lbs. per square inch may be generated in jacket 23. This high pressure steam is supplied through conduits 24 and 25 to the accumulator vessels and serves to charge them at approximately this pressure. Due to this high pressure itis desirable to have the accumulator plant consist of a plurality of comparatively small vessels rather than a single large vessel. The advantages resulting from the series connection are fully dis-v cussed and this arrangement is claimed per se in my copending application of which this is a division. 3

Assuming the accumulator plant to be fully charged in the manner just described, generator I0 is able to carry the normal load of the turbine by supplying steam through steam line [3 to high pressure section [4. In this section the steam is partially expanded and then passes to low pressure section If: where it is completely expanded, the exhaust steam passing to the condenser l9. In the event of a sudden increase in. the load imposed on the turbine, the latter will slow down somewhat and governor l8 opens. valve I! to a greater extent. If generator I0 is not able to supply sufficient steam to operate the turbine under the increased load, the pressure in steam line l3 falls and valve 36 is opened. The pressure in line l3 would also fall if, for any reason, the amount of steam supplied by generator It was reduced. Steam now passes from the accumulator vessels 33 and 34 through the conduit and valve 66 to the superheater coil 61 located in the steam space of vessel 28. Valve 58 located in conduit 62 may be kept closed in order that the pressure will be maintained, in vessels 2'! and 28, whereby the steam passing through superheater 61 is superheated in the manner described in my copending. application of which this is a division. Valve 66 acts as a pressure reducing valve to reduce the pressure of the steam supplied by the accumulators to approximately boiler pressure. This. steam passes through conduit 16 and check valve II to main steam line l3 and thence passes with the steam supplied by generator ID to the high pressure section M. In the event the condition of increased load is maintained for a time long enough to cause the pressurein theaccumulator vessels 29through 34 drop to approximately boiler pressure, valve 14. opens and thereafter accumulator steam is supplied only to the low pressure section I of the turbine. In this manner the accumulators may be fully discharged.

Recharging of the accumulators from time to time is regulated by valve 5|. In the event that generator II! is supplying more steam than is necessary to operate the turbine, the pressure and consequently the temperature of this steam in conduit I3 in the neighborhood of thermostatic element 52 will be high, which will cause valve 5| to open and also start pump M. This causes water to be supplied to jacket 23 and heat is abstracted from the steam in conduit I3 in order to heat the water in the jacket and to convert it into steam which is supplied, in the manner above described, to the accumulator plant.

When the accumulator plant is fully charged, vessels 29, 30, 3| and 32 are completely filled with water. However, steam is withdrawn from vessels 33 and 34, this reduces somewhat the pressure in all the vessels if valve 58 is open, or in vessels 29 through 34 if the valve is closed. This reduction in pressure causes the evaporation of water in each vessel and the resulting steam through check valve 63 to the next vessel. The check valve, however, prevents the backfiow of liquid and hence the steam space formed by the evaporation of liquid is maintained.

There is always a certain amount of heat lost due to radiation and conduction from the accumulator vessels. Consequently, even if no steam is being withdrawn through valve 66, it nevertheless is necessary to supply steam through nozzles 26 in order to compensate for this loss. This results in an increase in the fluid content of the vessels and hence an increase in the liquid level in vessels 33 and 34. If this increase in level is sufficient, float BI opens valve 80 and permits the withdrawal of steam even though valve 66 is closed. The heat content of the steam taken from the accumulator plant through valve 80 is less than the heat content of the steam supplied through noZZles 25, and this surplus heat compensates for the heat losses.

Valve 80 also serves to regulate the degree of superheat of the steam supplied to high pressure section I4 of the turbine. When the accumulator is not fully charged, heat is removed from the superheated steam as it heats the water in jacket 23. If valve 80 were not provided, when the accumulator became fully charged, circulation through the jacket would cease and no heat would be extracted from the superheated steam, and the degree of superheat might be too great for the high pressure section. However, valve 80 opens when the accumulator is fully charged and permits the discharge of steam through conduit I0 to the main line I3, even though valve 66 is closed. Thereupon, heat is transferred from the superheated steam to the fluid in jacket 23 to bring the accumulator up to full charge. The net result is that heat at a high temperature is removed from the steam in line I3 to the fluid in jacket 23 and returned to the line I3 at a lower temperature in the s,

steam supplied through conduit ID, the accumulator plant thus acting as a de-superheater.

The above described steam plant is also particularly well adapted to be used in conjunction with an electric net work in which there is available at times excess electric energy, generated for instance by means of a hydro-electric plantv Reference character designates an alternator driven by a water turbine and supplying electric energy to the line 9|. An electric steam generator 92 is connected by means of conduits 93 and 94 in parallel with jacket 23. In the event that alternator 90 produces excess current, switch 95 may be closed and this current supplied to generator 92 where it produces high pressure steam which is fed through conduits 93 and 25 to the accumulator plant. Thus, steam generator I 0 might be omitted entirely, or serve merely as stand-by equipment, the accumulator being charged solely by excess electric energy produced by alternator 90, the accumulator plant being relied upon to supply steam for operating the steam turbine at time of peak load.

In Fig. 2 there is shown more in detail a preierred construction of the heat exchanger in= eluding main steam line I3 and jacket 23. As shown, members I3 and 23 are arcuate, whereby they may expand and contract unequally without setting up excessive strains in the material. If a larger heat exchange surface is desired the arrangement shown in Fig. 3 may be employed. As shown in this figure, main line I3 is divided into a plurality of conduits I3a, I31) and I30 which extend through jackets 23a, 23b and 230.

Accumulator vessels 2'! through 34 may be arranged in the manner shown in Fig, 4. As here shown, the tanks are secured together by means of saddles 91 and the tanks are covered by a common layer of insulating material 98.

While I have shown one more or less specific application of my invention to a particular type of plant, it is to be understood that this has been done for purposes of illustration only and that the scope of my invention is not to be limited thereby, but is to be determined by the appended claim.

What I claim is:

In a steam plant, a steam boiler, means for superheating steam generated by said boiler, a high pressure steam consumer supplied with the superheated steam, a steam accumulator, a two compartment surface heat exchanger disposed exteriorly of said accumulator, one compartment being supplied with superheated steam and the other compartment being supplied with water whereby the water is heated to produce steam having a temperature corresponding to a pressure higher than the pressure of the superheated steam, means for introducing the high pressure water into said accumulator to thereby charge the accumulator at a pressure above boiler pressure, means for supplying steam to said high pressure consumer from said accumulater while the accmnulator pressure remains above boiler pressure, a low pressure consumer, and means for supplying steam to said low pressure consumer when the accumulator pressure drops below boiler pressure.

PAUL GILLI. 

